I can usually find a soft spot in my heart for just about any kind of animal, but I try very hard to make an exception for slugs, lice and sawflies. And aphids (Aphidinae). I wouldn't mind so much if they spread themselves out a bit, but no: they refuse to eat anything else except for the youngest and most tender of shoots on our roses.

(unidentified) aphids (Aphidinae) on two of the rose bushes in our garden

That said, it's very difficult not to feel some sense of admiration for the critters. Aphids can be parthenogenetic during most of their lives. They can be oviparous and/orviviparous at different times during the year. During spring and summer all aphids are parthenogenetic and viviparous: females give birth to other females with no eggs or mating in sight. Look at them long enough and you're ound to see aphids excreting aphids that immediately start eating and start excreting other aphids:

And if that wasn't mind-boggling enough: the newborn aphid not only already has a daughter developing in it, but that daughter most often already has a developing granddaughter inside it.

Aphids in all sorts of colours: green, pink & black

Some aphids that are parthenogenic in summer develop both females and males as winter approaches. Males and females mate and the eggs overwinter, to hatch into new parthenogenic females in spring. Other aphids have a special overwintering stage (a hiernalis), and in yet other aphids the adult form overwinters.

A leaf of aphids, just about ready for overwintering

In our garden most aphids seem to overwinter under the leaves of overhanging plants:

Aphids in winter. Left: aphid and (very) juvenile slug.

Aphids are notoriously difficult to identify, and it's often not even clear if it's a white aphid or a moldy aphid:

Left: a woolly aphid (I think), right: a black aphid on a dry leaf of grass

Some ants farm aphids for their honeydew, the surplus sugar they excrete when sucking the sap out of plants:

Small black ants (Lasius niger) milking aphids.
Left: September 2004, outside the front door. Right: May 2005, in the garden.